Lindsay Lohan believes Charlie Sheen is in the midst of a “life or death situation” … and has told friends she’s “thrilled” that he’s checked himself into a rehab center.

Sources close to Lohan tell us … Lindsay is “worried” about Sheen because his most recent bender shows “obvious signs of addiction” … something Lindsay knows about all too well.

But after Sheen decided to check himself into a treatment center Friday afternoon, Lohan is confident he can get his life back together … if he commits himself to sobriety.

We’re told Lindsay “understands the problem of having the wrong people around and wants Charlie to understand that he needs to surround himself with positive, sober people.”

Bitch please. Lindsay only wants Charlie Sheen to sober up because she’s bitter than she’s never invited to his parties and because it means there will be more blow for her. And also because, you know, it means we’ll write about her here.